In the last two decades Kohn-Sham density functional theory (KS-DFT) has become the most widely used electronic structure method in chemistry. This success stems from the low computational cost of the method in comparison with ab initio
electronic structure methods based on the many-electron wavefunction. Unfortunately, although formally exact, density functional theories involve a contribution to the energy whose form is unknown. This exchange-correlation energy must be approximated in practice. The accuracy and utility of DFT is thus critically dependent on the quality of these approximations.
Whilst progress has been made in developing improved functionals, a number of deficiencies still remain, which lead to problems describing specific types of bonding, bond dissociation and weak interactions. As linear scaling implementations open up the possibility to perform DFT calculations for many 1000’s of atoms the need to remedy these weaknesses is becoming increasingly clear.
My research focusses on various aspects of these exchange-correlation functionals and the details of their evaluations. In particular I am interested in the prospects for using the very robust, accurate and systematic ab initio
methods to directly guide the construction of new more accurate density functional methods.